Virtualized OCSSDs spanning physical OCSSD channels

ABSTRACT

A system includes reception of a request from a first application to create a virtual open-channel solid state drive associated with a first bandwidth and first capacity, association, in response to the request, of block addresses of a virtual address space of the first application with block addresses of one or more blocks of a first one of a first plurality of channels of a first open-channel solid state drive and with block addresses of one or more blocks of a second one of the first plurality of channels, reception, from the first application, of a first I/O call associated with one or more block addresses of the virtual address space, determination of block addresses of one or more blocks of the first one of the first plurality of channels which are associated with the one or more block addresses of the virtual address space, and execution of the first I/O call on the determined block addresses of one or more blocks of the first one of the first plurality of channels.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 15/850,578, filed Dec. 21, 2017, the contents of which areincorporated herein by reference for all purposes.

BACKGROUND

Solid-state drives (SSDs) are increasingly used to serve cloud andclient workloads. Traditionally, an application accesses a SSD via apage-based filesystem Application Programming Interface (API) providedby an operating system. A block layer of the operating system thenissues corresponding block-based commands to the SSD. The commands arereceived by a flash translation layer of the SSD, which executes thecommands on the SSD hardware in a flash-efficient manner. The multiplesoftware layers lying between the application and the SSD hardwarecontribute significantly to transaction overhead, particularly ascompared to the fast access speeds of SSDs.

The above-described traditional architecture allows multipleapplications to access storage across several SSD channels. SSD storageis presented to each application as a file (i.e., a virtual hard drive)to which any available SSD storage unit can be allocated and from whichany available SSD storage unit can be deallocated rather seamlessly.Bandwidth consumption per application may be controlled bysoftware-based file throttling mechanisms. Again, however, the softwarelayers of the architecture result in poor performance.

Open-channel solid-state drives (OCSSDs) provide increased efficiencyand performance by allowing OCSSD-compatible applications to directlyaccess SSD hardware, without the intervening software layers of thetraditional architecture. However, the number of applications that canaccess a set of OCSSDs is limited by the number of actual physicalchannels provided by the OCSSDs. Assuming a data server includes fouridentical OCSSDs and each OCSSD includes eight channels, the server cansupport a maximum of thirty-two applications. Each of the thirty-twoapplications would receive the same amount of storage and same level ofperformance/bandwidth.

What is needed is a system to virtualize OCSSDs across multiple physicalOCSSD channels, while efficiently providing security isolation andperformance isolation.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a system architecture to provide virtualopen-channel SSDs to applications according to some embodiments.

FIG. 2 is a block diagram of a system architecture to provide a virtualopen-channel SSD to an application according to some embodiments.

FIG. 3 is a flow diagram of a process to create and utilize a virtualopen-channel SSD according to some embodiments.

FIG. 4 is a block diagram of a system architecture including a dataserver including physical open-channel SSDs and providing virtualopen-channel SSDs to applications executing on an application serveraccording to some embodiments.

FIG. 5 is a block diagram of a system architecture including a dataserver including physical open-channel SSDs and providing virtualopen-channel SSDs to applications executing on an application serveraccording to some embodiments.

FIG. 6 is a block diagram of a system architecture including two dataservers including physical open-channel SSDs and providing virtualopen-channel SSDs to applications executing on an application serveraccording to some embodiments.

FIG. 7 is a block diagram of a system architecture including two dataservers including physical open-channel SSDs and providing virtualopen-channel SSDs to applications executing on two application serversaccording to some embodiments.

FIG. 8 is a block diagram of a system architecture to provide virtualopen-channel SSDs to applications according to some embodiments.

FIG. 9 is a block diagram of data server including physical open-channelSSDs and providing virtual open-channel SSDs according to someembodiments.

DETAILED DESCRIPTION

The following description is provided to enable any person in the art tomake and use the described embodiments. Various modifications, however,will remain readily apparent to those in the art.

Generally, some embodiments provide an efficient system-level solutionfor virtualizing OCSSDs across multiple physical OCSSD channels whileensuring security and performance isolation. Security isolation requiresthat one application is prevented from accessing OCSSD storage allocatedto another application, and performance isolation dictates that thebandwidth and capacity consumption of one application does not affectthe ability of another application to use its allocated bandwidth andcapacity. Embodiments may therefore allow multiple (e.g., hundreds) ofapplications to share limited (e.g., eight) OCSSDs while alsoexperiencing the performance benefits of OCSSDs.

Some embodiments address the technical problem of efficiently sharingSSD hardware resources among applications. A technical solution to thetechnical problem, according to some embodiments, includes providingsoftware and/or hardware logic to create virtualized OCSSDs spanningphysical OCSSD channels and to provide applications with efficientaccess thereto.

FIG. 1 is a block diagram of an architecture to provide virtualopen-channel SSDs to applications according to some embodiments. TheFIG. 1 architecture may be implemented using any number of suitablecomputing devices and networks.

Applications 102 a through 102N may comprise processor-executableprogram code executed by one or more application servers or othersuitable devices. According to some embodiments, applications 102 athrough 102N may be executed by one or more application servers toprovide functionality to remote client devices (not shown). One or moreof applications 102 a through 102N may be executed within a dedicatedvirtual machine provided by a server as is known in the art.

Each of applications 102 a through 102N requires access to data storagehardware. The data storage hardware may be used to store any data usedby an application, including but not limited to key-value stores,indexes, and multi-dimensional data stores. As shown, some embodimentsexpose one or more private logical OCSSDs (i.e., virtual OCSSDs, orVOCSSDs) to each application.

In particular, each one of applications 102 a through 102N communicateswith a respective set of VOCSSDs 112 a through 112N. A set of VOCSSDs112 a through 112N may include one or more VOCSSDs. Each VOCSSD of a setof VOCSSDs 112 a through 112N represents physical resources of one ormore of OCSSDs 132 through 138 of data storage array 130.

As is known in the art, each of OCSSDs 132 through 138 comprises aFlash-based memory device including a number of data channels, a numberof dies within each channel, a number of planes within each die, and anumber of blocks within each die. OCSSDs differ from a traditional SSDin that they expose the physical storage units of the SSD to the hostwithout an intervening flash translation layer. The host may thereforemanage data placement, I/O scheduling, wear-levelling, garbagecollection, and/or other functions previously performed by the flashtranslation layer.

A data storage array 130 according to some embodiments is not limited tofour OCSSDs. Also, the number of applications which arecontemporaneously served by an architecture according to someembodiments may far outnumber the number of underlying OCSSDs (e.g., bya ratio of 50-to-1).

According to some embodiments, and in contrast to conventional systems,any VOCSSD of VOCSSDs 112 a through 112N may virtualize blocks locatedwithin die of any two or more channels of OCSSDs 132 through 138. Forexample, a VOCSSD of VOCSSDs 112 a virtualizes blocks located within dieof two channels of a same OCSSD. In another example, a VOCSSD of VOCSSDs112 c may virtualize blocks located on a die of a channel of OCSSD 132and blocks located on a die of a channel of OCSSD 138. Application 102a, which issues page-addressed calls to read, write and erase blocks ofthe VOCSSD of VOCSSDs 112 c, therefore causes reading, writing anderasing of the physical blocks located on the die of the channel ofOCSSD 132 and the physical blocks located on the die of the channel ofOCSSD 138. The access to OCSSD 132 and OCSSD 138 is transparent toapplication 102, which issues the read, write and erase calls withrespect to its own virtual address space and not with respect to theaddresses of the actual physical block.

Each VOCSSD of FIG. 1 is depicted using a dashed line. The dashed linerepresents logical virtualized storage. An application's calls to anassociated VOCSSD are received and executed by kernel 120 according tosome embodiments. Kernel 120 comprises an operating system kernel of adata server associated with data storage array 130. The data server maybe located remotely from array 130 or within a same physical chassis.

Kernel 120 includes VOCSSD kernel driver 122. According to someembodiments, kernel driver 122 receives requests for OCSSD capacity andbandwidth from applications 102 a through 102N. Based on the requests,VOCSSD kernel driver 122 maps virtual block addresses of eachapplication's address space to physical block addresses within theOCSSDs of array 130. VOCSSD kernel driver 122 uses the mappingassociated with an application to determine physical OCSSD blockaddresses which correspond to any read, write and erase calls receivedfrom the application. VOCSSD kernel driver 122 thereby provides securityisolation by ensuring that an application only reads or writes to aphysical OCSSD block which has been allocated to the application, andthat no application reads or writes to a physical OCSSD block which hasbeen allocated to another application via a mapping.

A request for OCSSD capacity and bandwidth received by VOCSSD kerneldriver 122 may specify a number of blocks, and a number of channels anda number of dies across which the blocks should be striped. The numberof blocks represents the requested capacity, and the number of channelsand dies is directly proportional to the bandwidth. VOCSSD kernel driver122 thereby also provides performance isolation because, once allocatedvia a mapping, the bandwidth and capacity consumption of one applicationdoes not affect another application's ability to use its allocatedbandwidth and capacity.

As described above, kernel driver 122 maps calls received from anapplication to physical block addresses of OCSSDs 132 through 138. Themapped calls are provided to OCSSD device driver 124, which passes thecalls to storage array 130 and receives output therefrom via a suitableinterface as is known in the art. According to some embodiments, theinterface conforms to the NVMe specification or a subset thereof.

FIG. 2 illustrates an implementation of the FIG. 1 architectureaccording to some embodiments. Applications 202 and 204 are executedwithin respective virtual machines 205 and 207. Virtual machines 205 and207 may be provided by one or two application servers.

Applications 202 and 204 employ software libraries 206 and 208 to call ablock-address based storage interface provided by kernel driver 222 ofkernel 220. For example, application 202, using library 206, may call anIOCTL interface to create a VOCSSD according to some embodiments. Thecall may specify an allocation policy consisting of a number of blocks,a number of channels, and a number of die. Resource manager 223 ofkernel driver 222 may implement the interface to determine a set ofphysical blocks of OCSSDs 232 through 238 which satisfy the allocationpolicy, and to generate a table 224 which maps the virtual address spaceof application 202 (e.g., 0-64 Gb) to the physical addresses of thedetermined blocks.

Similarly, application 204 may use library 208 to call the IOCTLinterface to create a VOCSSD associated with application 204. The callmay specify a second allocation policy consisting of a second number ofblocks, number of channels, and number of die. In response to the call,resource manager 223 determines second physical blocks of OCSSDs 232through 238 which satisfy the second allocation policy, and generates asecond table 224 which is associated with application 204. The secondtable 224 maps the virtual address space of application 204 (e.g., 0-32Gb) to the physical addresses of the determined second blocks. Tables224 may be stored in a cache or other volatile memory of data server 220for fast access thereto.

Once a VOCSSD has been generated for an application, the application mayissue IOCTL calls which refer to block addresses of the application'svirtual address space. Address translation component 225 of kerneldriver 222 receives such calls and uses the table 224 corresponding tothe application to maps the calls to physical block addresses of OCSSDs232 through 238. The mapped calls are provided to OCSSD device driver227, which in turn calls a suitable interface provided by storage array230 to execute the calls. OCSSD device driver 227 is a component ofkernel driver 222 in the FIG. 2 architecture, but embodiments are notlimited thereto. According to some embodiments, the calls may operatedirectly on the blocks of OCSSDs 232 through 238 rather than utilizingany flash translation layer of OCSSDs 232 through 238.

FIG. 3 comprises a flow diagram of process 300 to create and utilize avirtual open-channel SSD according to some embodiments. In someembodiments, a processing unit (e.g., one or more processors, processingcores, processor threads, etc.) of a data server executes softwareprogram code to cause the data server to perform process 300. Process300 and all other processes mentioned herein may be embodied incomputer-executable program code read from one or more of non-transitorycomputer-readable media, such as a floppy disk, a CD-ROM, a DVD-ROM, aFlash drive, and a magnetic tape, and then stored in a compressed,uncompiled and/or encrypted format. In some embodiments, hard-wiredcircuitry may be used in place of, or in combination with, program codefor implementation of processes according to some embodiments.Embodiments are therefore not limited to any specific combination ofhardware and software.

Prior to process 300, an application transmits a request to create aVOCSSD. As described above, the application may transmit the request byusing a VOCSSD-supporting library to call an application programminginterface of a kernel driver of a data server.

The request is received from the application at S310. The request mayspecify a storage capacity and a bandwidth of the desired VOCSSD.According to some embodiments, the storage capacity may be expressed inbytes, blocks or any other suitable unit of storage capacity. Thebandwidth may be represented by a number of channels and a number ofdies across which the storage capacity should be allocated. One exampleof the syntax of the request is IOCTL_CREATE_VOCSSD (size_in_blocks,num_channels, num_die), but embodiments are not limited thereto. Therequest may specify other configuration information, includinginformation related to fault-tolerance, such as a number of physicalOCSSDs, a number of data servers and/or a number of storage arraysacross which the storage capacity should be allocated.

Next, at S320, a mapping is defined between a virtual address space ofthe application and a physical address space of one or more OCSSDs. Thephysical address space is determined based on the bandwidth and capacityspecified in the request, and may span at least two OCSSD channels.According to some embodiments, S320 is executed by resource manager 223of kernel driver 222 and the mapping comprises a table 224. Resourcemanager 223 may use table metadata to associate the table 224 with theapplication from which the request was received, for example.

An I/O control call is received from the application at S330. The I/Ocontrol call may comprise a system call requesting device-specific I/Ooperations from kernel 220. The I/O control call is associated with oneor more addresses of the virtual address space. The application issuesthe I/O control call in order to read from and write to the VOCSSDduring application execution. According to some embodiments, theapplication may utilize the aforementioned library to call a readinterface (e.g., IOCTL_READ_SECTOR (virtual_sector_address)), a writeinterface (e.g., IOCTL_WRITE_PAGE (virtual_page_address)) and/or anderase interface (e.g., IOCTL_ERASE_BLOCK (virtual_block_address))implemented by the kernel driver.

According to some embodiments, address translation component 225 ofkernel driver 222 receives the I/O control call at S330 and determinesone or more physical addresses of the physical address space at S340.The one or more physical addresses are determined based on the mapping,and correspond to the one or more addresses of the virtual address spacespecified in the received call. The call is executed on the one or morephysical addresses at S350, and a result is returned to the application.According to some embodiments, OCSSD device driver 227 calls a suitableinterface provided by storage array 230 to execute the call on the oneor more physical addresses of OCSSDs 232 through 238.

Process 300 may be executed with respect to many applications inparallel. Such execution may result in the creation of a mapping tablecorresponding to each application, with each mapping table mappingbetween the virtual address space of a respective application and aphysical address space of dedicated physical blocks which are allocatedto the application and may span two or more OCSSD channels.

As mentioned above, some embodiments leverage the ability of an OCSSD toallow direct access to its physical blocks, without an intervening flashtranslation layer. Some embodiments of a kernel driver and/or an OCSSDdevice driver may therefore perform flash-related functions such aswear-leveling, garbage collection and write amplification reduction. Forexample, the kernel driver may allocate less-worn blocks to moreaggressive applications and/or may periodically change pointers within amapping table to point to different physical blocks which also meet thecapacity and bandwidth requirements associated with the mapping table.

FIGS. 4 through 7 illustrate variations of the above-describedarchitecture according to some embodiments. Embodiments are not limitedto the architectures of FIGS. 4 through 7.

FIG. 4 illustrates application server 410 executing a plurality ofapplications. One or more of the applications of application server 410may read from and write to OCSSDs of data server 420 via a dedicatedVOCSSD provided by kernel 425 of data server 420 as described above.Each dedicated VOCSSD may provide access to physical blocks of differentchannels of one or more of the OCSSDs of data server 420. Data server420 may similarly and contemporaneously serve data to one or moreapplications executing on one or more other application servers. Asdescribed above, the VOCSSDs are allocated and served in a manner whichensures security and performance isolation between all of theapplications accessing the OCSSDs of data server 420.

FIG. 5 illustrates application server 510 executing a plurality ofapplications which read data from and write data to data server 520 asdescribed above. Data server 520 is in communication with remotenetwork-attached storage device 530, including an array of OCSSDs.According to some embodiments, a VOCSSD provided by data server 520 mayinclude physical blocks from one or more channels of the OCSSDs of dataserver 520 and/or from one or more channels of the OCSSDs ofnetwork-attached storage 530. Therefore, a mapping table generated bykernel 525 in association with an application may map virtual addressesof the application to physical block addresses of any of the OCSSDs ofdata server 520 and any of the OCSSDs of network-attached storage 530.Embodiments may include any number of externally-located OCSSDs fromwhich blocks may be allocated to a single VOCSSD.

FIG. 6 illustrates distributed resource management according to someembodiments. Upon receiving a request from an application of applicationserver 610 to create a VOCSSD as described above, kernel 625 of dataserver 620 may communicate with kernel 635 to map block addresses of theOCSSDs of data server 630 and block addresses of the OCSSDs of dataserver 620 to the virtual addresses of the VOCSSD. Such a mapping mayoccur if the request specifies that blocks of the VOCSSD should spanmultiple data servers.

FIG. 7 is similar to FIG. 6 in that VOCSSDs associated with applicationsof application server 710 may be associated with physical blocks locatedin data server 720 and/or data server 740. Also similarly, anapplication of application server 730 may transmit a request to create aVOCSSD to kernel 745 of server 740. In response, kernel 745 of dataserver 740 may communicate with kernel 725 to map block addresses of theOCSSDs of data server 720 as well as block addresses of the OCSSDs ofdata server 740 to the virtual addresses of the VOCSSD.

FIG. 8 illustrates a hardwired implementation of the logic of theabove-described VOCSSD kernel driver. In particular, FPGA 820 performsthe functions attributed above to a VOCSSD kernel driver. Such ahardware implementation may introduce less latency than a softwareimplementation of the VOCSSD kernel driver. Any suitable one or moreother hardware logic devices may be used in place of FPGA 820. Accordingto some embodiments, FPGA 820 acts as a SR-IOV target, providing PCIvirtualization to a privileged device.

FIG. 9 is a block diagram of system 900 according to some embodiments.System 900 may comprise a general-purpose data server and may executeprogram code to perform any of the functions described herein. System900 may include other unshown elements according to some embodiments.

System 900 includes processing unit 910 operatively coupled tocommunication device 920, data storage system 930, one or more inputdevices 940, one or more output devices 950, volatile memory 960 andOCSSDs 972 through 978. Processing unit 910 may comprise one or moreprocessors, processing cores, etc. for executing program code.Communication device 920 may facilitate communication with externaldevices, such as remote application servers and data servers. Inputdevice(s) 940 may comprise, for example, a keyboard, a keypad, a mouseor other pointing device, a microphone, a touch screen, and/or aneye-tracking device. Output device(s) 950 may comprise, for example, adisplay (e.g., a display screen), a speaker, and/or a printer.

Data storage system 930 may comprise any number of appropriatepersistent storage devices, including combinations of magnetic storagedevices (e.g., magnetic tape, hard disk drives and flash memory),optical storage devices, Read Only Memory (ROM) devices, etc. Memory 960may comprise Random Access Memory (RAM), Storage Class Memory (SCM) orany other fast-access memory. OCSSDs 972 through 978 may comprise acommonly-managed array of OCSSDs as known in the art.

Kernel driver 932 and OCSSD device driver 934 may comprise program codeexecuted by processing unit 910 to cause system 900 to perform any oneor more of the processes described herein. In this regard, addressmapping tables 936 may store mappings between virtual addresses ofclient applications and channel-spanning physical block addresses ofOCSSDs 972 through 978 as described herein. Data storage device 930 mayalso store data and other program code for providing additionalfunctionality and/or which are necessary for operation of system 900,such as other device drivers, operating system files, etc.

The foregoing diagrams represent logical architectures for describingprocesses according to some embodiments, and actual implementations mayinclude more or different components arranged in other manners. Othertopologies may be used in conjunction with other embodiments. Moreover,each component or device described herein may be implemented by anynumber of devices in communication via any number of other public and/orprivate networks. Two or more of such computing devices may be locatedremote from one another and may communicate with one another via anyknown manner of network(s) and/or a dedicated connection. Each componentor device may comprise any number of hardware and/or software elementssuitable to provide the functions described herein as well as any otherfunctions.

Embodiments described herein are solely for the purpose of illustration.Those in the art will recognize other embodiments may be practiced withmodifications and alterations to that described above.

What is claimed is:
 1. A system comprising: a first open-channel solidstate drive comprising a first plurality of channels, each of the firstplurality of channels comprising a respective plurality of blocks; and adata server comprising a processing unit to execute program code tocause the data server to: associate block addresses of a virtual addressspace of a first application with block addresses of one or more blocksof a first one of the first plurality of channels and with blockaddresses of one or more blocks of a second one of the first pluralityof channels; receive, from the first application, a first I/O callassociated with one or more block addresses of the virtual addressspace; determine block addresses of one or more blocks of the first oneof the first plurality of channels which are associated with the one ormore block addresses of the virtual address space; and execute the firstI/O call on the determined block addresses of one or more blocks of thefirst one of the first plurality of channels.
 2. The system according toclaim 1, wherein the processing unit is to execute program code to causethe data server to: receive, from the first application, a second VOcall associated with a second one or more block addresses of the virtualaddress space; determine block addresses of one or more blocks of theone of the second one of the first plurality of channels which areassociated with the second one or more block addresses of the virtualaddress space; and execute the second VO call on the determined blockaddresses of one or more blocks of the second one of the first pluralityof channels.
 3. The system according to claim 1, further comprising asecond open-channel solid state drive located remote from the firstopen-channel solid state drive.
 4. The system according to claim 1,wherein the processing unit is to execute program code to cause the dataserver to: receive, from the first application, a second VO callassociated with a second one or more block addresses of the virtualaddress space; determine block addresses of a second one or more blocksof the first one of the first plurality of channels which are associatedwith the second one or more block addresses of the virtual addressspace; and execute the second VO call on the determined block addressesof the second one or more blocks of the first one of the first pluralityof channels.
 5. The system according to claim 1, wherein the processingunit is to execute program code to cause the data server to: associateblock addresses of a virtual address space of a second application withblock addresses of a second one or more blocks of a third one of thefirst plurality of channels and with block addresses of a second one ormore blocks of a fourth one of the first plurality of channels; receive,from the second application, a second VO call associated with one ormore block addresses of the virtual address space of the secondapplication; determine block addresses of one or more blocks of thethird one of the first plurality of channels which are associated withthe one or more block addresses of the virtual address space of thesecond application; and execute the second VO call on the determinedblock addresses of one or more blocks of the third one of the firstplurality of channels which are associated with the one or more blockaddresses of the virtual address space of the second application.
 6. Acomputer-implemented method comprising: receiving a request from a firstapplication to create a virtual open-channel solid state driveassociated with a first bandwidth and first capacity; in response to therequest, associating block addresses of a virtual address space of thefirst application with block addresses of one or more blocks of a firstone of a first plurality of channels of a first open-channel solid statedrive and with block addresses of one or more blocks of a second one ofthe first plurality of channels of the first open-channel solid statedrive; receiving, from the first application, a first I/O callassociated with one or more block addresses of the virtual addressspace; determining block addresses of one or more blocks of the firstone of the first plurality of channels which are associated with the oneor more block addresses of the virtual address space; and executing thefirst I/O call on the determined block addresses of one or more blocksof the first one of the first plurality of channels.
 7. The methodaccording to claim 6, wherein associating block addresses of the virtualaddress space of the first application with block addresses of one ormore blocks of the first one of the first plurality of channels and withblock addresses of one or more blocks of the second one of the firstplurality of channels comprises: associating block addresses of thevirtual address space of the first application with block addresses ofone or more blocks of the first one of the first plurality of channels,with block addresses of one or more blocks of the second one of thefirst plurality of channels, and with block addresses of one or moreblocks of a third one of the first plurality of channels.
 8. The methodaccording to claim 7, further comprising: receiving, from the firstapplication, a second VO call associated with a second one or more blockaddresses of the virtual address space; determining block addresses ofone or more blocks of the third one of the first plurality of channelswhich are associated with the second one or more block addresses of thevirtual address space; and executing the second VO call on thedetermined block addresses of one or more blocks of the third one of thefirst plurality of channels.
 9. The method according to claim 6, furthercomprising: receiving, from the first application, a second VO callassociated with a second one or more block addresses of the virtualaddress space; determining block addresses of one or more blocks of thesecond one of the first plurality of channels which are associated withthe second one or more block addresses of the virtual address space; andexecuting the second VO call on the determined block addresses of one ormore blocks of the second one of the first plurality of channels. 10.The method according to claim 6, further comprising: receiving a requestfrom a second application to create a second virtual open-channel solidstate drive associated with a second bandwidth and second capacity; inresponse to the request, associating block addresses of a virtualaddress space of the second application with block addresses of a thirdone or more blocks of the first one of the first plurality of channelsand with block addresses of a fourth one or more blocks of the first oneof the second plurality of channels; receiving, from the secondapplication, a second VO call associated with one or more blockaddresses of the virtual address space of the second application;determining block addresses of one or more blocks of the third one ofthe first plurality of channels which are associated with the one ormore block addresses of the virtual address space of the secondapplication; and executing the second VO call on the determined blockaddresses of one or more blocks of the third one of the first pluralityof channels which are associated with the one or more block addresses ofthe virtual address space of the second application.
 11. The methodaccording to claim 10, wherein associating the block addresses of thevirtual address space of the first application with block addresses ofone or more blocks of the first one of the first plurality of channelsand with block addresses of one or more blocks of the second one offirst plurality of channels comprises creating a first mapping tableassociated with the first application, wherein the first mapping tablemaps the block addresses of the virtual address space of the firstapplication with block addresses of one or more blocks of the first oneof the first plurality of channels and with block addresses of one ormore blocks of the second one of the first plurality of channels,wherein associating the block addresses of the virtual address space ofthe second application with block addresses of the one or more blocks ofthe third one of the first plurality of channels and with blockaddresses of the one or more blocks of the fourth one of the firstplurality of channels comprises creating a second mapping tableassociated with the second application, and wherein the second mappingtable maps the block addresses of the virtual address space of thesecond application with block addresses of the one or more blocks of thethird one of the first plurality of channels and with block addresses ofthe one or more blocks of the fourth one of the first plurality ofchannels.
 12. A non-transitory computer-readable medium storingprocessor-executable process steps executable by a processor of acomputing system to cause the computing system to: associate blockaddresses of a virtual address space of a first application with blockaddresses of one or more blocks of a first one of a first plurality ofchannels of a first open-channel solid state drive and with blockaddresses of one or more blocks of a second one of the first pluralityof channels, each of the first plurality of channels comprising arespective plurality of blocks; receive, from a first application, afirst I/O call associated with one or more block addresses of thevirtual address space; determine block addresses of one or more blocksof the first one of the first plurality of channels which are associatedwith the one or more block addresses of the virtual address space; andexecute the first I/O call on the determined block addresses of one ormore blocks of the first one of the first plurality of channels.
 13. Thenon-transitory computer-readable medium according to claim 12, whereinthe processor-executable process steps are executable by a processor ofa computing system to cause the computing system to: receive, from thefirst application, a second VO call associated with a second one or moreblock addresses of the virtual address space; determine block addressesof one or more blocks of the one of the second one of the firstplurality of channels which are associated with the second one or moreblock addresses of the virtual address space; and execute the second VOcall on the determined block addresses of one or more blocks of thesecond one of the first plurality of channels.
 14. The non-transitorycomputer-readable medium according to claim 12, wherein theprocessor-executable process steps are executable by a processor of acomputing system to cause the computing system to: receive, from thefirst application, a second VO call associated with a second one or moreblock addresses of the virtual address space; determine block addressesof a second one or more blocks of the first one of the first pluralityof channels which are associated with the second one or more blockaddresses of the virtual address space; and execute the second VO callon the determined block addresses of the second one or more blocks ofthe first one of the first plurality of channels.
 15. The non-transitorycomputer-readable medium according to claim 12, wherein theprocessor-executable process steps are executable by a processor of acomputing system to cause the computing system to: associate blockaddresses of a virtual address space of a second application with blockaddresses of a second one or more blocks of a third one of the firstplurality of channels and with block addresses of a second one or moreblocks of a fourth one of the first plurality of channels; receive, fromthe second application, a second VO call associated with one or moreblock addresses of the virtual address space of the second application;determine block addresses of one or more blocks of the third one of thefirst plurality of channels which are associated with the one or moreblock addresses of the virtual address space of the second application;and execute the second VO call on the determined block addresses of oneor more blocks of the third one of the first plurality of channels whichare associated with the one or more block addresses of the virtualaddress space of the second application.